SAN JOSE, Calif. — No men’s figure skater seems better positioned to win a gold medal at the 2018 Winter Olympics than Nathan Chen, the 18-year-old jumping prodigy from the United States. Or better positioned to thrust a word into the lexicon of the casual fan: “quad.”

The word will be repeated often this week at the United States championships here, and next month at the Olympics in Pyeongchang, South Korea.

The jump in which a skater spins four revolutions in the air, known in the sport as a quad, has been performed in competition for two decades. But it has become a necessary and defining maneuver of risk and audacity, indispensable for victory. And Chen stands out as the first to complete five quads in a four-and-a-half-minute routine.

It is a feat that requires superb technique and enormous stamina. And it is a way to quantify the abstract, to give familiar numerical access to a sport in which the scoring can seem forbidding and impenetrable.

Fans don’t need to know a Lutz from a Salchow or a loop from a toe loop to be engaged by men’s skating at the Olympics. They don’t have to give a flip about a flip. They have the quad as an easily understood yardstick of success, like track’s four-minute mile or a 300-yard drive in golf.

And yet the sport itself is being roiled by the quad. Controversy abounds about the direction of skating under the current scoring system, which was adopted after a judging scandal at the 2002 Olympics in Salt Lake City scuttled the classic method in which 6.0 was the highest possible score.

The current scoring system assigns a specific number points for each element of skating, including jumps, spins and musical interpretation. For instance, there is a base value of 13.6 points for a quad Lutz, 12.3 for a quad flip, 12 for a quad loop, 10.5 for a quad Salchow and 10.3 for a quad toe loop. (No one has landed a quad Axel, worth a base of 15 points, in competition.)

To proponents, skating is now more readily assessable and impartial, more fully a sport. To critics, today’s system favors a scavenger hunt for points over artistic expression and gives short shrift to other appealing aspects of the sport like choreography, footwork, flair, and a sense of theater. The tension between objectivity and subjectivity is inevitable and ceaseless.

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Chen falling at a competition in Finland in April. Dick Button, the 1948 and 1952 Olympic champion, noted that skaters still receive points for falling on a quad jump.CreditJohn Macdougall/Agence France-Presse — Getty Images

For aficionados of the quad, like Chen, full of soaring teenage exhilaration, the perfect jump feels easy and addictive. “It’s like you get a high off the jumps, and you crave it and you want to do it again and again and again,” he said in an interview. “I haven’t found that anywhere else.”

For others, the reliance on the quad has effectively reduced figure skating to a math test. There is a proposal by international skating officials to reduce the numerical value of quad jumps after these Olympics in an attempt to restore more balance between skating’s athleticism and artistry.

The American skating legend Dick Button, the 1948 and 1952 Olympic champion, said, “I don’t even enjoy watching skating today because it’s all about quadruple jumps.”

The winner of the 2018 Olympics, he said with resignation on a recent teleconference call, will be the skater who performs “the best and the most quadruple jumps, period, end of subject.”

Button, always frank as a commentator, might seem bitterly nostalgic and hypocritical to some, given that he was essentially the Nathan Chen of the mid-20th century. Button pushed the technical envelope and is credited with being the first man to perform a double Axel — the only style of jump where skaters take off in a forward position. He is also credited as being the first to perform any jump requiring three revolutions.

Yet Button’s wariness about the quad might resonate with sports fans in general. He noted that skaters still receive points even if they fall on a quad jump, leading to more attempts and infecting some competitions with inelegant spills on the ice.

“If you’re a pole vault jumper and you knock the pole off its supports, do you get points for it?” Button said.

In fairness, Chen has worked diligently to improve his artistry and skating skills, as well. He understands that the quad alone will not bring him a gold medal. And Yuzuru Hanyu of Japan, the reigning Olympic champion, performs with deftness, creativity and emotion that may be unmatched by any previous skater. But Hanyu is recovering from a serious ankle injury sustained, in part, because of his attempt to keep up with Chen’s mastery of the quad. Hanyu’s Olympic prospects are uncertain.

Chen has worked diligently to improve his artistry and skating skills.CreditToshifumi Kitamura/Agence France-Presse — Getty Images

From October to December, Chen won three important competitions and defeated Hanyu along the way. Yet, just as the quad has tested the athletic boundaries of the sport, it has made for a number of flawed, flailing performances among the top male skaters.

Research by Philip Hersh, a prominent figure-skating writer from Chicago who has covered 10 Winter Olympics, found that only three medalists had skated clean short and long programs at major international competitions since 2015.

Although Chen is undefeated in his Olympic buildup, he has had his uncertain moments. A new skate blade disrupted his jumping at the Skate America Grand Prix competition in November, in Lake Placid, N.Y. Chen’s coach also cited poor technique and lagging confidence, among other issues.

During Chen’s free skate at the last important Olympic tuneup, the Grand Prix final in Japan in December, he seemed alternately tentative and hurried. He fell on a quad toe loop, awkwardly landed a quad flip and a quad Lutz and reduced a planned quad Salchow to two revolutions. At the finish, he shook his head.

Chen finished first, but the NBC announcer Johnny Weir, a two-time Olympian, said on air that, sometimes with younger skaters, “They put all these quads in, almost like over-excited shoppers on Black Friday, just filling their carts with too much stuff they aren’t ready for. And then they rush through and make silly mistakes.”

Last week, in a teleconference call, Chen said he had since missed some practice time but declined to reveal why. He brushed off any suggestion that his shopping cart, or skating as a whole, was overloaded with quads.

Increasing the frequency of the quad was “upping the risk” and a “good progression,” Chen said. “Obviously there’s a limit. We have been using the competitions to figure out where that limit is.”

If the rules change next season, Chen said, he will adjust. For now, there is an Olympic gold medal to seek. He plans two quads in his short program at the national championships and five in his long program. And he will reassess his strategy at the Olympics, for which he is virtually certain to qualify.

Sure, expectation adds pressure, Chen acknowledged. But he has reminded himself to embrace the moment. To be considered a favorite at the Olympics, he said, is “what I’ve wanted for a long time.”

A version of this article appears in print on , on Page B6 of the New York edition with the headline: A Jump That’s Upsetting Skating’s Balance. Order Reprints | Today’s Paper | Subscribe